Application of Color Metallography to Study the Microstructure of Friction Stir-Welded Dual-Phase Brass Using Various Etchants

Abstract

Brass is difficult to join using conventional fusion welding processes due to the loss of zinc during fusion. The relatively new friction stir welding (FSW) is a promising process to join brass without loss of zinc. The aim of the present work is to join 6-mm-thick Cu–38.55Zn brass using FSW and investigate the microstructure using color metallography. Two color etchants, namely Beraha 13a and Beraha 12a, were used to reveal the microstructure. The welded joints showed various zones due to the application of frictional heat and severe plastic deformation. The microstructure of heat affected zone was identical to that of base metal. The weld zone consisted of fine equiaxed grains due to dynamic recrystallization. Partial crystallization was observed along the thickness direction in the weld zone. The micrographs obtained using Beraha 12a etchant were better to that of Beraha 13a etchant.